This glossary was created with input from members of PICNet, PHAC Infection Control Guidelines and the BC Ministry of Health. A list of references is available here. Definitions will be updated frequently and may change or be removed. Please send us your comments and feedback by email to picnet@phsa.ca.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Canadian Nosocomial Infection Surveillance Program: CNISP is a national surveillance program that provides statistics and data on nosocomial infections in Canada for use in the development and evaluation of guidelines (10).
Carrier: A person or animal that harbors a specific infectious agent in the absence of discernable clinical disease and serves as a potential source of infection. The carrier state may occur in an individual with an infection that is inapparent throughout it’s course (known as health or asymptomatic carrier) or during the incubation period, convalescence or post-convalescence of an individual with a clinically recognizable disease (known as incubatory carrier or convalescent carrier). The carrier state may be of short or long term duration. (11)
Case: In epidemiology, a person in the population or study group identified as having the particular disease, health disorder or condition under investigation. A variety of criteria may be used to identify cases: e.g. diagnosis, registries and notifications, abstracts of clinical records, reporting of defects such as a dental record. The epidemiologic definition of a case is not necessarily the same as the ordinary clinical definition. (11)
Case Definition: A set of diagnostic criteria that must be fulfilled in order to identify a person as a case of a particular disease. Case definition can be based on clinical, laboratory or combined clinical and laboratory criteria or a scoring system with points for each criterion that matches the features of the disease. If the diagnosis is based on a scoring system e.g. Multiple Sclerosis, it is important to abide by the system for surveillance purposes and when deciding whether to include or exclude cases in an epidemiologic study. (11)
Cleaning: The physical removal of foreign material e.g. dusts, soil, organic material such as blood, secretions, excretions and microorganisms using mechanical and/or chemical means. Cleaning physically removes rather than kills microorganisms. (20)
Cluster: A grouping of cases of a disease within a specific time frame and geographic location suggesting a possible association between the cases with respect to transmission. (18)
Cohort: Two or more patients colonized or infected with the same organism that are separated physically, in a separate room or ward, from other patients who are not colonized or infected with that organism (9).
Cohort Staffing: The practice of assigning specified personnel to care only for patients/residents known to be colonized or infected with the same organism. Such personnel would not participate in the care of patients/residents who are not colonized or infected with that organism (9).
Colonization:The presence and multiplication in or on the body of microorganism(s) without any symptoms of infection or detected immune reaction. Colonization is often a natural process in the development of natural “normal flora”. (1)
Communicable: Capable of being transmitted from one person to another; synonymous with “infectious” and “contagious” (9).
Communicable disease: an illness due to a specific infectious agent or its toxic products that arises through transmission of that agent or its products from an infected person, animal, or reservoir to a susceptible host, either directly or indirectly through an intermediate plant of animal host, vector or the inanimate environment. (11)
Communicable period: the time during which an infectious agent may be transferred directly or indirectly from an infected person to another person, from an infected animal to humans or from an infected person to an animal, including arthropods. (11)
Community: A group of individuals organized into a unit, or manifesting some unifying trait or common interest; loosely, the locality or catchment area population for which a service is provided, or more broadly, the state, nation or body politic. (11)
Contact Transmission: The transmission of infectious agents by direct contact or indirect contact. Direct contact occurs when the transfer of microorganisms results from direct physical contact between an infected or colonized individual and a susceptible host (body surface to body surface). Indirect contact involves the passive transfer of microorganisms to a susceptible host via an intermediate object such as contaminated instruments or other inanimate objects in the patient’s immediate environment. (9)
Confounder, Confounding variable: A variable that can be used to decrease confounding Bias when properly adjusted for. The identification of confounders requires expert or substantive knowledge about causal network of which exposure and outcome are part (e.g. pathophysiological and clinical knowledge). Attempts to select confounders solely based on observed statistical associations may lead to bias. (17)
Contact Transmission Precautions: Work practices to reduce the risk of transmitting infectious agents by direct or indirect contact with an infectious person (5).
Contagious: Capable of being transmitted from one person to another; synonymous with “infectious” and “communicable” (9).
Contamination: The presence of microorganisms on inanimate objects, e.g. clothing and surgical instruments, or microorganisms on body surfaces such as hands, or in substances e.g. water and food (9).
Cost/Benefit Analysis: A numerical evaluation of the actual or proposed value of specific process, including calculating the cost of the program and comparing that to the financial outcomes in the form of savings which can be expected from the program. (20)
Cumulative incidence:Proportion of a group (cohort) of people at risk who experience the onset of a health-related event during a specified time interval; this interval is generally the same for all members of the group, but as in lifetime incidence, it, may vary from person to person without reference to age. (20)
Critical items: instruments and devices that enter sterile tissues, including the vascular system. Critical items present a high risk of infection if the item is contaminated with any microorganisms, including bacterial spores. Reprocessing critical items involves meticulous cleaning followed by sterilization. (20)
Cross-infection: Infection of one person with pathogenic organisms from another and vice versa. Not the same as Nosocomial infection, which occurs in a health care setting; cross-infection can occur anywhere e.g. military barracks, a school, a workplace. (11)
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